GigaWaM project concludes, successfully tests WM-PON system

At the end of September 2012, the European-funded FP7 project “GigaWaM” reached a successful conclusion, participants say. The consortium of nine project partners asserts the results lay the foundation for the next generation of FTTx networks by successfully proving concepts and design for all the critical junction points of a WDM-PON.

The technology developed under this program enables a protocol-independent, multichannel, high-speed, DWDM-based access network to be realized at a very attractive cost-performance level, satisfying the ever increasing demand for higher bandwidth for quite some time to come, the members add.

The project objective was to develop components and packaging technologies for the next-generation high-speed access network. The principle challenge was that the cost of data transmission via wavelength-multiplexing architectures is dominated by the cost of packaging. The project aimed to develop a system with an integration scale approximately 100X higher than the current state of the art, which can be implemented as a seamless upgrade to existing passive optical network (PON) infrastructures without requiring changes or re-routing of optical fibers.

The key technical objectives of the GigaWaM project were to implement 64 channels of 50-GHz channel spacing, delivering 1.25-Gbps symmetric bandwidth per wavelength across a distance of 20 km on a single fiber. All key objectives had been achieved, the partners declare.

The project, launched in 2008, saw Sweden’s Syntune AB (which was acquired by Ignis during the program, and then sold to Finisar as part of a larger deal) develop a tunable C-Band laser for operation between 50° and 70°C for subscriber units, Vertilas GmbH of Germany develop L-Band vertical-cavity surface-emitting laser (VCSEL) arrays for central office transmitters, and Ignis Photonyx AS in Denmark (also acquired by Finisar) develop the passive optical components such as a flat-top arrayed waveguide grating (AWG) for central office use, an athermal AWG for the remote node, L/C-Band filters, and integration platforms. The hybridization of the optical components was undertaken by Aifotec AG (also in Germany).

To achieve the aggressive cost targets, innovative packaging techniques and features have were developed to reduce component count and keep the number of precision alignment steps to a minimum. Additionally the optical engine hybridization concept developed has been optimized for automatic assembly.

The final tests at the Technical University of Denmark’s Department of Photonics Engineering, DTU/Fotonik, demonstrated the optical power loss of only 20 dB over a 20-km distance, providing a comfortable margin in the overall power budget. Despite the narrow channel spacing, no interference between channels was seen. The system was shown to scale to at least 2.5 Gbps, limited by receiver sensitivity only.

An automatic laser tuning system has also been developed using the remote node AWG as the wavelength reference for each channel. This approach ensures optimal performance for the lifetime of a GigaWaM access network, according to the project partners.

The project was coordinated by Nor-Tek, a subsidiary of Pera Technology Ltd (UK).

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